JPH01271915A - Magnetic storage body and magnetic storage device and its manufacture - Google Patents

Abstract

PURPOSE:To improve corrosion resistance, to reduce coefficient of friction and to maintain long-time reliability by covering a metal magnetic film with an oxide film of the metal element which constitutes the magnetic film, carbonaceous film, and metallic salt of fatty acid. CONSTITUTION:On the metal magnetic film, the oxide film of the metal element which constitutes the magnetic medium, for example Fe2O3, is formed by exposing to a gas plasma which contains oxygen gas, etc. Then the carbonaceous film such as graphite is formed by sputtering, and further the metallic salt of fatty acid is formed thereon by spraying, etc. The oxide film protects the metal magnetic film from corrosive factors such as water and chlorine. The carbonaceous film and metallic salt of fatty acid ensure the wear resistance. Even if a magnetic head penetrates to the carbonaceous film, the head will not damage the magnetic film owing to the low coefficient of friction and incohesiveness of the oxide film.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to magnetic storage devices (magnetic disk devices, magnetic drum devices, and magnetic tape devices) and magnetic storage bodies (hereinafter referred to as storage bodies) used in the magnetic storage devices. ) and its manufacturing method.

[Conventional technology]

A storage body having a metal magnetic medium (hereinafter referred to as all four media) must have sufficient mechanical reliability to withstand contact with a recording/reproducing head (hereinafter referred to as a head) and must be free from moisture, chlorine, etc. Corrosion resistance is required to withstand corrosive environments.

Conventionally, the substrates used are At alloy substrates, glass plates, ceramic plates, etc., which have been subjected to alumite treatment or non-magnetic plating treatment such as N1-P plating, and then polished to make them mirror-finished or have a surface density. P.

After non-magnetic plating such as Ni-Ou-P and coating with Or, Bi, etc., a ferromagnetic metal medium is coated, and then Si is coated.
n, (including polysilicic acid), ktN, O.

Si, N, and kt20. A protective film such as a solid solution of is coated, and a thin layer of a liquid lubricant typified by Per70 polyether or a solid lubricant typified by higher alcohol or fatty acid is further coated.

Although the above-mentioned memory bodies have a certain level of durability and have already begun to appear on the market, they have major drawbacks.

A magnetic storage device equipped with the above storage body was heated at 40℃80%R.
If left in an environment of H., corrosion points will occur in one or two places on one memory body, leading to defect errors. Furthermore, repeated contact between the storage body and the head increased the coefficient of friction between them, often causing the spindle motor to stop.

[Problem to be solved by the invention]

Conventional techniques have had the problem of not being able to ensure sufficient corrosion resistance of the metal medium, and not being able to ensure sufficient mechanical reliability between the storage body and the head.

The present invention solves the above problems, and its purpose is to dramatically improve the corrosion resistance of metal media in environments containing moisture and chlorine, and to improve the coefficient of friction between the storage body and the head. It is an object of the present invention to manufacture and provide a highly reliable memory body that can significantly reduce the amount of water and maintain its effect for a long period of time, and to provide a magnetic memory device using the memory body.

[Means to solve the problem]

In the present invention, a metal magnetic medium is coated on a substrate, a thin oxide film of a metal element constituting the metal magnetic medium is coated on the metal magnetic medium, and then a carbonaceous thin film is coated on the oxide thin film. and is further coated with a metal salt of a fatty acid.

The metal medium is formed using the same materials and manufacturing methods as in the prior art. That is, 00. An alloy made of IFe, Or, Ni, P, noble metals, etc. is formed by a dry film forming method such as wet plating, sputtering, or the like.

The oxide of the metal element constituting the metal medium is Co3O
4, Fe, O5, 0rb1, etc. can be obtained by dry film forming methods such as PVD and OVD methods, and wet film forming methods such as thermal decomposition of organometallic compounds, but the most suitable method is oxygen This is a method in which oxides are grown by exposing them to plasma of a gas containing gas. Film thickness is 50-200K
is appropriate.

Carbon thin films are graphite and diamond.

Amorphous, single, mixed, laminated, 100 to 50
A film thickness of 0^ is appropriate. Film formation is done by sputtering method,
This can be done by a dry film forming method such as a PVD method such as an ion blasting method or an OVD method.

Metal salts of fatty acids can be saturated, unsaturated or straight chain.

It is a salt of a fatty acid and a metal, which has no restrictions on branching properties, and is generally referred to as a soap or metal soap.
metals and salts. These may be used alone or in combination, diluted with a soluble solvent, applied by a known manufacturing method such as a spray method, a spinner method, a dipping method, or an ultrasonic spray method, and baked if necessary. The ratio of solvent dilution is appropriately determined depending on the desired film thickness. Also, firing is at 50-150℃
A time of 1 minute to 820 minutes is sufficient, and a film thickness of 20 to 1 soX is appropriate.

[Effect]

According to the present invention, a metal medium is coated with an oxide thin film that has excellent hardness, denseness, and insulation properties, and is less likely to adhere to the head material. Particularly, by plasma treatment of a gas containing oxygen gas, deposits on the metal medium are removed, and a thin oxide film with extremely few pinholes and excellent adhesion to the metal medium is coated.

The thin oxide film protects the metal medium from corrosive agents such as moisture and chlorine. In addition, a thin film of carbonaceous material and a thin film of metal salt of fatty acid are used to ensure wear resistance between the head and the head, but repeated impact wear on the head causes the head to pass through the thin film of carbonaceous material and damage the metal media. This resulted in fatal damage to the head, resulting in head clarity. In the present invention, even when the head passes through the carbonaceous film, it does not come into direct contact with the metal medium, and the low coefficient of friction and non-adhesive properties of the oxide thin film cause almost no damage to the head.

As described above, it has become possible to manufacture and provide a memory body with excellent long-term mechanical reliability and storage reliability, and furthermore, by using the memory body, the reliability of a magnetic memory device has been significantly improved.

〔Example〕

After applying non-magnetic N1-P alloy plating to a thickness of approximately 15 μm on a surface-finished disk-shaped aluminum alloy substrate, the surface roughness Rα = 70 to 120X, Rmax is achieved by polishing.
= 7oo ~ 15oo, and the surface weight is processed and further c
o-Ni-P alloy plating was applied to a thickness of approximately 105 μm.

Next, set the above substrate in a magnetron sputtering device,
After evacuation to 5 x 10-' torr, oxygen gas was introduced to set the pressure to 0-1 tOrr, and an oxide thin film was grown on the metal medium by applying RF (substrate as cathode) at 400 W for the processing time shown in Table 1. .

Next, the introduction of oxygen gas was stopped and the 5 × 10-”to
After evacuation to rr, Ar gas was introduced, and a carbonaceous thin film was formed using the target shown in Table 1 at a power density of 4 W/-.

Furthermore, metal salts of fatty acids shown in Table 1 were mixed with methanol and Freon 11 g'Vco, o s w/v% (1'
)'l + degree diluted and dipping method (j Ocm /
m).

Table 1 Memory bodies manufactured by the above manufacturing method and 3370 type thin film head (Fly 0.15μ door p 977
A magnetic storage device was manufactured using L/see) and evaluated by the following test. The results are shown in Table 2.

(Ga ss durability test O3S operation (rise and fall time 10 seconds)
Determine the change in appearance before and after, the coefficient of static friction, and the rate of decrease in output.

(2) Corrosion Resistance Test The product was left in an environment of 80°C and 90% R, H, and after the time had passed, the number of missing bits was measured, and the time when the number of missing bits increased was determined to be the end of its life.

Table 2 [Effects of the Invention] Magnetic storage devices using thin-film eclipses have been on the market for a long time as storage media compatible with high recording densities, but their use is limited to some due to concerns about long-term reliability. It was getting worse.

According to the present invention, even if a memory medium is used in heating process, the metal medium will not be affected in any way in practical terms, and the mechanical reliability will be improved even with heads that are becoming increasingly hard and have low fly-hide. Since it is expensive, even if it is further miniaturized and installed in a magnetic storage device used in harsh environments, there will hardly be any noticeable deterioration in the characteristics of both the storage body and the head.

As described above, manufacturing of highly durable memory bodies compatible with high recording density,
Applicant: Seiko Epson Corporation

Claims (6)

[Claims] (1) A metal magnetic medium is coated on a substrate, a thin oxide film of a metal element constituting the metal magnetic medium is coated on the metal magnetic medium, and then a carbonaceous thin film is coated on the oxide thin film. , a magnetic memory further coated with a metal salt of a fatty acid. (2) A magnetic storage device characterized by using the magnetic storage body according to item 1. (3) A step of forming a metal magnetic medium on the substrate, then a step of forming an oxide thin film of a metal element constituting the metal magnetic medium on the metal magnetic medium, and then a carbonaceous thin film on the oxide thin film. 1. A method for manufacturing a magnetic memory body, comprising the steps of: forming a thin film of a metal salt of a fatty acid on the carbonaceous thin film; (4) Manufacture of the magnetic storage body according to item 3, characterized in that a thin oxide film of the metal magnetic medium is formed by exposing the substrate coated with the metal magnetic medium to plasma of a gas containing at least oxygen gas. Method. (5) A magnetic memory obtained by the manufacturing method described in item 4. (6) A magnetic storage device characterized by using the magnetic storage body according to item 5.